Fluid device

Abstract

A device including a substrate and a channel formed in a layer disposed on the substrate. The layer includes a cavitation layer and a passivation layer to mitigate the effects of hydrodynamic cavitation on a surface of the channel. The passivation and cavitation material and thickness are optimized thermally to nucleate and eject a bubble at low voltages. A resistive heating element is disposed within the channel that is activated to create a micro-fluidic pump to advance a fluid through the channel. A sensor is disposed within the channel to measure a characteristic of the fluid passing through the channel.

What is claimed is: 
     
         1 . A device comprising:
 a substrate;   a channel formed in a plurality of layers disposed on the substrate, wherein the plurality of layers are selected to have a thickness for operation at a low-voltage, the plurality of layers including a passivation layer and a cavitation layer to mitigate the effects of hydrodynamic cavitation on a surface of the channel;   a resistive heating element disposed within the channel, the resistive heating element being activated to create a micro-fluidic pump to advance a fluid through the channel; and   a sensor disposed within the channel to measure a characteristic of the fluid passing through the channel.   
     
     
         2 . The device of  claim 1  wherein the cavitation layer has a thickness of about 500 Å to about 2500 Å. 
     
     
         3 . The device of  claim 1  wherein the passivation layer has a thickness of about 500 Å to about 1500 Å. 
     
     
         4 . The device of  claim 1  wherein the resistive heating element has a thickness of about 500 Å to about 1500 Å. 
     
     
         5 . The device of  claim 1  wherein the resistive heating element comprises tantalum. 
     
     
         6 . The device of  claim 1  wherein the sensor has a thickness of about 1500 Å to about 3000 Å. 
     
     
         7 . The device of  claim 1  wherein the sensor is to measure one of an impedance, a capacitance, and a resistance associated with the fluid. 
     
     
         8 . The device of  claim 1  wherein a material and the thickness of each of the passivation layer and the cavitation layer are selected to be thermally optimized to nucleate and eject a bubble from the fluid at low voltages. 
     
     
         9 . A micro-fluidic sensor device comprising:
 a substrate;   a plurality of thin film layers on a first surface of the substrate, at least two of the layers forming a passivation layer and a cavitation layer;   a resistive heater on the substrate adjacent the ejection port; and   at least one channel in an encapsulation layer, the at least one channel providing a pathway from an injection port through the substrate, and to an ejection port formed in the encapsulation layer.   
     
     
         10 . The micro-fluidic sensor device of  claim 9  further comprising a sensor comprising gold. 
     
     
         11 . The micro-fluidic sensor device of  claim 9  further comprising at least one additional sensor. 
     
     
         12 . The micro-fluidic sensor device of  claim 9  wherein the fluid is blood. 
     
     
         13 . A method of forming a device comprising:
 forming a plurality of thin film layers on a first surface of a substrate, the plurality of thin film layers comprising a passivation layer and a cavitation layer;   forming a resistive heater on the substrate adjacent an ejection port formed in the encapsulation layer; and   forming at least one channel in an encapsulation layer, the at least one channel providing a pathway from an injection port through the substrate, through the channel, and through the ejection port.   
     
     
         14 . The method of  claim 13  wherein the cavitation layer has a thickness of about 500 Å to about 2500 Å, and the passivation layer has a thickness of about 500 Å to about 1500 Å. 
     
     
         15 . The method of  claim 13  wherein the ejection port resides adjacent to the resistive heater.